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T: macpdu2wireshark: dump to file instead of sending UDP packets

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In NR with several layers, we may have MAC PDU of size bigger than 64KB,
which does not fit into a UDP buffer, destroying macpdu2wireshark.

Let's add an option to dump to a pcap file instead of using UDP packets.
The DLT 252 magic is used (check wireshark documentation to understand).
Run macpdu2wireshark with -h to see how to configure wireshark to read
the produced files.
This commit is contained in:
Cedric Roux
2025-05-23 11:07:26 +02:00
parent b2c9a1d2b5
commit ae650bc9ea
2 changed files with 173 additions and 40 deletions
Download Patch File Download Diff File Expand all files Collapse all files
common/utils/T/DOC/T/wireshark.md
+10 -1
View File
@@ -3,7 +3,8 @@
First, read the [basic usage](./basic.md) to compile things.
It is possible to use `wireshark` to analyse MAC PDUs for UEs,
MIBs, SIBs, and random accesses seen by the eNodeB.
MIBs, SIBs, and random accesses seen by the eNodeB. It also
works for the gNB, as well as for the nrUE.
## Live usage
@@ -20,6 +21,14 @@ Then run:
./macpdu2wireshark -d ../T_messages.txt -live
```
Note: in some cases a MAC PDU may be bigger than the size of an UDP payload
(slightly less than 64 KiB). This is particularily the case for large
bandwidths in NR and MIMO. In this case macpdu2wireshark, sending UDP packets
in its default mode of operations, will fail. By using the option `-to-file`
a pcap file may be directly generated. You need to configure wireshark to
process the generated files (run `macpdu2wireshark -h` to see how to
configure wireshark for this case).
For other options of `macpdu2wireshark`, run:
```shell
common/utils/T/tracer/macpdu2wireshark.c
+163 -39
View File
@@ -115,6 +115,11 @@ typedef struct {
int max_sib;
int live;
int no_bind;
/* config to dump to file instead of UDP */
/* output_filename != NULL means to output to file */
char *output_filename;
FILE *output_file;
/* runtime vars */
int cur_mib;
int cur_sib;
@@ -129,19 +134,96 @@ typedef struct {
int nr_next_ue_id;
} ev_data;
/****************************************************************************/
/* direct output to pcap file */
/****************************************************************************/
void write_pcap_header(const char *filename, FILE *f)
{
/* see 'man pcap-savefile' for format */
uint32_t magic = 0xa1b23c4d; /* magic for second/nanosecond */
uint16_t major = 2;
uint16_t minor = 4;
uint32_t reserved = 0;
uint32_t snapshot_length = 0x7fffffff; /* let's be generous */
uint32_t link_layer_type = 252; /* DLT_WIRESHARK_UPPER_PDU */
if (fwrite(&magic, 4, 1, f) != 1
|| fwrite(&major, 2, 1, f) != 1
|| fwrite(&minor, 2, 1, f) != 1
|| fwrite(&reserved, 4, 1, f) != 1
|| fwrite(&reserved, 4, 1, f) != 1
|| fwrite(&snapshot_length, 4, 1, f) != 1
|| fwrite(&link_layer_type, 4, 1, f) != 1) {
printf("fatal: error writing header to %s\n", filename);
exit(1);
}
}
const char *pcap_trace_header(int is_lte)
{
static char header_nr[] = {
0x00, 12, /* type = EXP_PDU_TAG_DISSECTOR_NAME */
0x00, 16, /* length */
'm', 'a', 'c', '-', 'n', 'r', '-', 'f', 'r', 'a', 'm', 'e', 'd', 0, 0, 0,
0x00, 0x00, 0x00, 0x00 /* EXP_PDU_TAG_END_OF_OPT with length 0 */
};
static char header_lte[] = {
0x00, 12, /* type = EXP_PDU_TAG_DISSECTOR_NAME */
0x00, 16, /* length */
'm', 'a', 'c', '-', 'l', 't', 'e', '-', 'f', 'r', 'a', 'm', 'e', 'd', 0, 0,
0x00, 0x00, 0x00, 0x00 /* EXP_PDU_TAG_END_OF_OPT with length 0 */
};
return is_lte ? header_lte : header_nr;
}
void write_pcap_trace(const char *filename, FILE *f,
struct timespec sending_time,
const char *buf, int size, int is_lte)
{
uint32_t second = sending_time.tv_sec;
uint32_t nanosecond = sending_time.tv_nsec;
uint32_t length = size + 24;
/* untruncated_length == length, we dump everything */
uint32_t untruncated_length = length;
if (fwrite(&second, 4, 1, f) != 1
|| fwrite(&nanosecond, 4, 1, f) != 1
|| fwrite(&length, 4, 1, f) != 1
|| fwrite(&untruncated_length, 4, 1, f) != 1
|| fwrite(pcap_trace_header(is_lte), 24, 1, f) != 1
|| fwrite(buf, size, 1, f) != 1) {
printf("fatal: error writing to file %s\n", filename);
exit(1);
}
}
void write_pcap_trace_lte(const char *filename, FILE *f,
struct timespec sending_time,
const char *buf, int size)
{
write_pcap_trace(filename, f, sending_time, buf, size, 1);
}
void write_pcap_trace_nr(const char *filename, FILE *f,
struct timespec sending_time,
const char *buf, int size)
{
write_pcap_trace(filename, f, sending_time, buf, size, 0);
}
/****************************************************************************/
/* LTE */
/****************************************************************************/
void trace_lte(ev_data *d, int direction, int rnti_type, int rnti,
int frame, int subframe, void *buf, int bufsize, int preamble,
int sr_rnti)
void trace_lte(struct timespec sending_time, ev_data *d, int direction,
int rnti_type, int rnti, int frame, int subframe, void *buf,
int bufsize, int preamble, int sr_rnti)
{
ssize_t ret;
int fsf;
int i;
d->buf.osize = 0;
PUTS(&d->buf, MAC_LTE_START_STRING);
if (!d->output_filename)
PUTS(&d->buf, MAC_LTE_START_STRING);
PUTC(&d->buf, FDD_RADIO);
PUTC(&d->buf, direction);
PUTC(&d->buf, rnti_type);
@@ -202,16 +284,21 @@ void trace_lte(ev_data *d, int direction, int rnti_type, int rnti,
for (i = 0; i < bufsize; i++)
PUTC(&d->buf, ((char *)buf)[i]);
ret = sendto(d->socket, d->buf.obuf, d->buf.osize, 0,
(struct sockaddr *)&d->to, sizeof(struct sockaddr_in));
if (d->output_filename) {
write_pcap_trace_lte(d->output_filename, d->output_file, sending_time,
d->buf.obuf, d->buf.osize);
} else {
ret = sendto(d->socket, d->buf.obuf, d->buf.osize, 0,
(struct sockaddr *)&d->to, sizeof(struct sockaddr_in));
if (ret != d->buf.osize) abort();
if (ret != d->buf.osize) abort();
}
}
void ul(void *_d, event e)
{
ev_data *d = _d;
trace_lte(d, DIRECTION_UPLINK, C_RNTI, e.e[d->ul_rnti].i,
trace_lte(e.sending_time, d, DIRECTION_UPLINK, C_RNTI, e.e[d->ul_rnti].i,
e.e[d->ul_frame].i, e.e[d->ul_subframe].i,
e.e[d->ul_data].b, e.e[d->ul_data].bsize,
NO_PREAMBLE, NO_SR_RNTI);
@@ -229,7 +316,7 @@ void dl(void *_d, event e)
d->cur_sib++;
}
trace_lte(d, DIRECTION_DOWNLINK,
trace_lte(e.sending_time, d, DIRECTION_DOWNLINK,
e.e[d->dl_rnti].i != 0xffff ? C_RNTI : SI_RNTI, e.e[d->dl_rnti].i,
e.e[d->dl_frame].i, e.e[d->dl_subframe].i,
e.e[d->dl_data].b, e.e[d->dl_data].bsize,
@@ -245,7 +332,7 @@ void mib(void *_d, event e)
if (d->max_mib && d->cur_mib == d->max_mib) return;
d->cur_mib++;
trace_lte(d, DIRECTION_DOWNLINK, NO_RNTI, 0,
trace_lte(e.sending_time, d, DIRECTION_DOWNLINK, NO_RNTI, 0,
e.e[d->mib_frame].i, e.e[d->mib_subframe].i,
e.e[d->mib_data].b, e.e[d->mib_data].bsize,
NO_PREAMBLE, NO_SR_RNTI);
@@ -254,7 +341,7 @@ void mib(void *_d, event e)
void preamble(void *_d, event e)
{
ev_data *d = _d;
trace_lte(d, DIRECTION_UPLINK, NO_RNTI, 0,
trace_lte(e.sending_time, d, DIRECTION_UPLINK, NO_RNTI, 0,
e.e[d->preamble_frame].i, e.e[d->preamble_subframe].i,
NULL, 0,
e.e[d->preamble_preamble].i, NO_SR_RNTI);
@@ -263,7 +350,7 @@ void preamble(void *_d, event e)
void ue_preamble(void *_d, event e)
{
ev_data *d = _d;
trace_lte(d, DIRECTION_UPLINK, NO_RNTI, 0,
trace_lte(e.sending_time, d, DIRECTION_UPLINK, NO_RNTI, 0,
e.e[d->ue_preamble_frame].i, e.e[d->ue_preamble_subframe].i,
NULL, 0,
e.e[d->ue_preamble_preamble].i, NO_SR_RNTI);
@@ -272,7 +359,8 @@ void ue_preamble(void *_d, event e)
void rar(void *_d, event e)
{
ev_data *d = _d;
trace_lte(d, DIRECTION_DOWNLINK, RA_RNTI, e.e[d->rar_rnti].i,
trace_lte(e.sending_time, d, DIRECTION_DOWNLINK,
RA_RNTI, e.e[d->rar_rnti].i,
e.e[d->rar_frame].i, e.e[d->rar_subframe].i,
e.e[d->rar_data].b, e.e[d->rar_data].bsize,
NO_PREAMBLE, NO_SR_RNTI);
@@ -281,7 +369,7 @@ void rar(void *_d, event e)
void sr(void *_d, event e)
{
ev_data *d = _d;
trace_lte(d, DIRECTION_UPLINK, NO_RNTI, 0,
trace_lte(e.sending_time, d, DIRECTION_UPLINK, NO_RNTI, 0,
e.e[d->sr_frame].i, e.e[d->sr_subframe].i,
NULL, 0,
NO_PREAMBLE, e.e[d->sr_rnti].i);
@@ -310,14 +398,15 @@ void sr(void *_d, event e)
#define NR_C_RNTI 3
#define NR_SI_RNTI 4
void trace_nr(ev_data *d, int direction, int rnti_type, int rnti,
int frame, int slot, int harq_pid, void *buf, int bufsize,
int preamble)
void trace_nr(struct timespec sending_time, ev_data *d, int direction,
int rnti_type, int rnti, int frame, int slot, int harq_pid, void *buf,
int bufsize, int preamble)
{
ssize_t ret;
int i;
d->buf.osize = 0;
PUTS(&d->buf, MAC_NR_START_STRING);
if (!d->output_filename)
PUTS(&d->buf, MAC_NR_START_STRING);
PUTC(&d->buf, NR_TDD_RADIO);
PUTC(&d->buf, direction);
PUTC(&d->buf, rnti_type);
@@ -361,17 +450,23 @@ void trace_nr(ev_data *d, int direction, int rnti_type, int rnti,
for (i = 0; i < bufsize; i++)
PUTC(&d->buf, ((char *)buf)[i]);
ret = sendto(d->socket, d->buf.obuf, d->buf.osize, 0,
(struct sockaddr *)&d->to, sizeof(struct sockaddr_in));
if (d->output_filename) {
write_pcap_trace_nr(d->output_filename, d->output_file, sending_time,
d->buf.obuf, d->buf.osize);
} else {
ret = sendto(d->socket, d->buf.obuf, d->buf.osize, 0,
(struct sockaddr *)&d->to, sizeof(struct sockaddr_in));
if (ret != d->buf.osize) abort();
if (ret != d->buf.osize) abort();
}
}
void nr_ul(void *_d, event e)
{
ev_data *d = _d;
trace_nr(d, NR_DIRECTION_UPLINK, NR_C_RNTI, e.e[d->nr_ul_rnti].i,
trace_nr(e.sending_time, d, NR_DIRECTION_UPLINK,
NR_C_RNTI, e.e[d->nr_ul_rnti].i,
e.e[d->nr_ul_frame].i, e.e[d->nr_ul_slot].i,
e.e[d->nr_ul_harq_pid].i, e.e[d->nr_ul_data].b,
e.e[d->nr_ul_data].bsize, NO_PREAMBLE);
@@ -389,7 +484,7 @@ void nr_dl(void *_d, event e)
d->cur_sib++;
}
trace_nr(d, NR_DIRECTION_DOWNLINK,
trace_nr(e.sending_time, d, NR_DIRECTION_DOWNLINK,
e.e[d->nr_dl_rnti].i != 0xffff ? NR_C_RNTI : NR_SI_RNTI,
e.e[d->nr_dl_rnti].i, e.e[d->nr_dl_frame].i, e.e[d->nr_dl_slot].i,
e.e[d->nr_dl_harq_pid].i, e.e[d->nr_dl_data].b,
@@ -400,7 +495,8 @@ void nr_dl_retx(void *_d, event e)
{
ev_data *d = _d;
trace_nr(d, NR_DIRECTION_DOWNLINK, NR_C_RNTI, e.e[d->nr_dl_retx_rnti].i,
trace_nr(e.sending_time, d, NR_DIRECTION_DOWNLINK,
NR_C_RNTI, e.e[d->nr_dl_retx_rnti].i,
e.e[d->nr_dl_retx_frame].i, e.e[d->nr_dl_retx_slot].i,
e.e[d->nr_dl_retx_harq_pid].i, e.e[d->nr_dl_retx_data].b,
e.e[d->nr_dl_retx_data].bsize, NO_PREAMBLE);
@@ -416,7 +512,7 @@ void nr_mib(void *_d, event e)
d->cur_mib++;
trace_nr(d, NR_DIRECTION_DOWNLINK, NR_NO_RNTI, 0,
trace_nr(e.sending_time, d, NR_DIRECTION_DOWNLINK, NR_NO_RNTI, 0,
e.e[d->nr_mib_frame].i, e.e[d->nr_mib_slot].i, 0 /* harq pid */,
e.e[d->nr_mib_data].b, e.e[d->nr_mib_data].bsize, NO_PREAMBLE);
}
@@ -431,7 +527,7 @@ void nr_ue_mib(void *_d, event e)
d->cur_mib++;
trace_nr(d, NR_DIRECTION_DOWNLINK, NR_NO_RNTI, 0,
trace_nr(e.sending_time, d, NR_DIRECTION_DOWNLINK, NR_NO_RNTI, 0,
e.e[d->nr_ue_mib_frame].i, e.e[d->nr_ue_mib_slot].i, 0 /* harq pid */,
e.e[d->nr_ue_mib_data].b, e.e[d->nr_ue_mib_data].bsize, NO_PREAMBLE);
}
@@ -440,7 +536,8 @@ void nr_rar(void *_d, event e)
{
ev_data *d = _d;
trace_nr(d, NR_DIRECTION_DOWNLINK, NR_RA_RNTI, e.e[d->nr_rar_rnti].i,
trace_nr(e.sending_time, d, NR_DIRECTION_DOWNLINK,
NR_RA_RNTI, e.e[d->nr_rar_rnti].i,
e.e[d->nr_rar_frame].i, e.e[d->nr_rar_slot].i, 0 /* harq pid */,
e.e[d->nr_rar_data].b, e.e[d->nr_rar_data].bsize, NO_PREAMBLE);
}
@@ -449,7 +546,8 @@ void nr_ue_ul(void *_d, event e)
{
ev_data *d = _d;
trace_nr(d, NR_DIRECTION_UPLINK, NR_C_RNTI, e.e[d->nr_ue_ul_rnti].i,
trace_nr(e.sending_time, d, NR_DIRECTION_UPLINK,
NR_C_RNTI, e.e[d->nr_ue_ul_rnti].i,
e.e[d->nr_ue_ul_frame].i, e.e[d->nr_ue_ul_slot].i,
e.e[d->nr_ue_ul_harq_pid].i, e.e[d->nr_ue_ul_data].b,
e.e[d->nr_ue_ul_data].bsize, NO_PREAMBLE);
@@ -467,7 +565,7 @@ void nr_ue_dl(void *_d, event e)
d->cur_sib++;
}
trace_nr(d, NR_DIRECTION_DOWNLINK,
trace_nr(e.sending_time, d, NR_DIRECTION_DOWNLINK,
e.e[d->nr_ue_dl_rnti].i != 0xffff ? NR_C_RNTI : NR_SI_RNTI,
e.e[d->nr_ue_dl_rnti].i, e.e[d->nr_ue_dl_frame].i,
e.e[d->nr_ue_dl_slot].i, e.e[d->nr_ue_dl_harq_pid].i,
@@ -477,7 +575,8 @@ void nr_ue_dl(void *_d, event e)
void nr_ue_rar(void *_d, event e)
{
ev_data *d = _d;
trace_nr(d, DIRECTION_DOWNLINK, RA_RNTI, e.e[d->nr_ue_rar_rnti].i,
trace_nr(e.sending_time, d, DIRECTION_DOWNLINK,
RA_RNTI, e.e[d->nr_ue_rar_rnti].i,
e.e[d->nr_ue_rar_frame].i, e.e[d->nr_ue_rar_slot].i, 0,
e.e[d->nr_ue_rar_data].b, e.e[d->nr_ue_rar_data].bsize,
NO_PREAMBLE);
@@ -833,7 +932,15 @@ void usage(void)
" -live-port <port> tracee's port (default %d)\n"
" -no-bind don't bind to IP address (for remote logging)\n"
"-i and -live are mutually exclusive options. One of them must be provided\n"
"but not both.\n",
"but not both.\n"
"\n"
"Use the following options to dump to a file instead of sending UDP packets:\n"
" -to-file <filename> dump to file using the mac framed format\n"
"\n"
"To use wireshark with files created using the option '-to-file',\n"
"you need to configure wireshark:\n"
" in Analyze->Enabled Protocols search for MAC-NR-FRAMED and\n"
" MAC-LTE-FRAMED and enable them.\n",
DEFAULT_IP,
DEFAULT_PORT,
DEFAULT_LIVE_IP,
@@ -881,11 +988,13 @@ int main(int n, char **v)
if (!strcmp(v[i], "-live-ip")) { if(i>n-2)usage(); live_ip = v[++i]; continue; }
if (!strcmp(v[i], "-live-port")) { if(i>n-2)usage(); live_port = atoi(v[++i]); continue; }
if (!strcmp(v[i], "-no-bind")) { d.no_bind = 1; continue; }
if (!strcmp(v[i], "-to-file")) { if(i>n-2)usage(); d.output_filename = v[++i]; continue; }
usage();
}
if (database_filename == NULL) {
printf("ERROR: provide a database file (-d)\n");
printf("use -h for help on usage\n");
exit(1);
}
@@ -992,17 +1101,27 @@ int main(int n, char **v)
register_handler_function(h, nr_ue_dl_id, nr_ue_dl, &d);
register_handler_function(h, nr_ue_rar_id, nr_ue_rar, &d);
d.socket = socket(AF_INET, SOCK_DGRAM, 0);
if (d.output_filename) {
d.output_file = fopen(d.output_filename, "w");
if (d.output_file == NULL) {
perror(d.output_filename);
exit(1);
}
write_pcap_header(d.output_filename, d.output_file);
} else {
d.socket = socket(AF_INET, SOCK_DGRAM, 0);
if (d.socket == -1) {
perror("socket");
exit(1);
if (d.socket == -1) {
perror("socket");
exit(1);
}
d.to.sin_family = AF_INET;
d.to.sin_port = htons(port);
d.to.sin_addr.s_addr = inet_addr(ip);
new_thread(receiver, &d);
}
d.to.sin_family = AF_INET;
d.to.sin_port = htons(port);
d.to.sin_addr.s_addr = inet_addr(ip);
new_thread(receiver, &d);
OBUF ebuf = {.osize = 0, .omaxsize = 0, .obuf = NULL};
/* read messages */
@@ -1025,5 +1144,10 @@ int main(int n, char **v)
handle_event(h, e);
}
if (d.output_filename) {
if (fclose(d.output_file))
perror(d.output_filename);
}
return 0;
}